Fluorescent lamp



Jan. 18, 1949.

C. E. FA RRIS FLuo'hEscEuT LAMP I Filed Jul 14, 1947 V-MMMS PatentedJan. 18, 1949 2,459,633 FLUORESCENT LAMP Clarence E. Farris, FortMonroe, Va. Application July 14, 1947, Serial No. 760,782

This invention relates to fluorescent light bulbs. An object ofthis'invention is to provide an improved light bulb embodying an innerclosed tube or body and an outer envelope disposed in closely spacedrelation with respect to the inner tube, thereby forming a veryrestricted space within which a gaseous element is positioned and withinwhich space the electrodes are also positioned.

Another object of this invention is to provide a fluorescent light bulbwhich is so constructed and arranged as to produce a greater intensityof light due to the greater activity of the ions and the absence ofwasted gas radiations.

A further object of this invention is to provide a fluorescent lightbulb wherein there will be a more intimate contact between theultra-violet radiations and the fluorescent materials which will utilizethe maximum direct action of such materials rather than casual surfacecontact.

With the above and other objects in View, my invention consists in thearrangement, combination and details of construction disclosed in thedrawings and specification, and then more particularly pointed out inthe appended claims.

In the drawing,

Figure 1 is a longitudinal section of a fluorescent tube constructedaccording to an embodiment of this invention,

Figure 2 is a sectional view taken on the line 2-2 of Figure 1; and

Figure 3 is a diagrammatic view of the electrodes within the tube.

Referring to the drawing, the numeral l designates generally an outerenvelope or casing of transparent material such as glass or the like,which includes an elongated cylindrical body ll having end walls I! andI3.

3 Claims; (Cl. 176-122) 20 and 2| within which a pair of spiralelectrodes 22 and 23 are adapted to seat. The electrodes 22 and 23 areextended over the end wall l8 or the inner tube I and are then extendedThe end wall 12 is formed with a tubular nipple [4 through which theelectrodes to be hereinafter described are adapted to'be extended. Aninner closed tube generally designated as I5 is disposed within theenvelope l0 and includes a cylindrical body l6 formed with closedopposite ends l1 and I8,

The inner tube l5 forms a restricted cylindrical space or chamber [9within the envelope l0, which chamber is adapted to be evacuated andthen filled with a gaseous material or vapor, the gas being either neon,argon, or helium, and the vapor being a mercury vapor. If desired, theremay be a mixture of the gas and mercury vapor.

The cylindrical body l6 of the inner closed tube i5 is formed with apair of spiral grooves through the nipple M for connection with a sourceof electric current supply. Each electrode is preferably coated asindicated at 24 with a coating of thorium oxide and the body it of theinner tube I5 is then coated with a coating 25 which also engages atleast partly about the coating 24 of the electrodes.

The coating or covering 25 is formed of. porous fluorescent material inthe form of magnesium tungstate or other suitable fluorescent material.While the inner tube or body i5 is shown as being hollow and closed ateach end, it will bev understood that this body may be formed as asolid, the purpose of the body being primarily to form a restrictedchamber of substantially cylindrical configuration which is adapted tobe initially evacuated in any conventional manner and then filled withthe desired gaseous material.

It will be understood that the fluorescent tube herein disclosed mayhave connected'with at least one electrode, a conventional resistor anda condenser may be connected with or interposed in' the other electrodeexteriorly of the tube. With a fluorescent tube as herein beforedescribed, by confining the space within which the electrodes arepositioned and in which the gas or vapor is positioned, the reactionbetween the electrodes and the fluorescent material and gas or vaporwill be more active and will thereby produce a greater intensity oflight than is the case Where the electrodes are disposed at the oppositeends of the gasified tube as in conventional gaseous or fluorescenttubes. f

Furthermore, the provision of the inner body which produces the confinedor restricted gas space .will eliminate wasted gas radiations andproduce a maximum direct action in contrast to the casual surfacecontact embodied in conventional fluorescent tubes.

I do not mean to confine myself to the exact details of constructionherein disclosed but claim all variations falling within the purview ofthe J appended claims.

assess:

coating about said closed tube and said elcctrodes.

' 2. A gaseous discharge tube comprising an outer evacuated envelope, aclosed tube within said envelope and spaced therefrom forming a arestricted cylindrical space. said closed tube having a pair of spiralgrooves in the outer surface thereof, a pair of spiral electrodes seated10 Number insaidsptraigrooveaandamlorescentcoating' about said closedtube and said electrodes.

, CLARINCI I. FARMS.

summons mm The following reierences are or record in the iile oi thispatent:

' UNITED STATES PATENTS Name A Date 2,135,6;90 Addink et a1. Nov. 8, ms.

FOREIGN PATENTS Number Country Date 503,255 Great Britain Apr. 4, 1039

